There are several palpatory diagnostic and treatment methods that have been developed to evaluate characteristics of the musculoskeletal system. One method evaluates the relative position of bony protuberances within the cardinal planes, primarily the coronal and sagittal planes. This method can be used, for example, when evaluating lower body and lower limb musculoskeletal disorders, including osteo/rheumatoid arthritis, spinal cord and other central nervous system (CNS) disorders, CNS degenerative diseases, low back pain, pelvic pain, postural and gait abnormalities, and obstetrics-gynecological disorders. Literature indicates that this form of testing has been used for at least a century, but a system to objectively evaluate the accuracy of the performance of this type of testing has only recently been considered.
The pelvis is one example of a region of the body where these tests are routinely used by clinicians in several manual medicine disciplines, including osteopathic physicians, chiropractors, physical therapists, for example. Pelvic landmarks commonly evaluated are the iliac crests, the anterior superior iliac spine (ASIS), the posterior superior iliac spine (PSIS), the pubic tubercles and the ischial tuberosities.
Muscle contraction during walking and running has been shown to cause changes in the relative position of the pelvic bones and thus their associated landmarks. For over a century, anecdotal reporting has proposed that when the relative position of the pelvic bones becomes too asymmetric, the pelvic joints (sacroiliac joints and pubic symphysis) lose mobility so when muscles pull on them, compression of joint surfaces, abnormal movement characteristics, and pain often results. Manual interventions have been designed to diminish the asymmetry of these landmarks and improve pelvic bone movement characteristics, which anecdotally have been associated with improved function and pain reduction/resolution. Consequently this method of manual testing, evaluating positional asymmetry of landmarks, has both diagnostic and treatment outcome functions.
Evaluating the validity of landmark asymmetry testing has been challenged by the lack of a methodology to objectively measure landmark asymmetries. Direct determination of positional asymmetry of pelvic landmarks in living humans (in vivo), for example, does not exist at this time. There remains a need, therefore, for a system that allows accurate control of the relative position of bones that exhibit asymmetry, such as the pelvic bones, using models of the human pelvis. The system should allow for an objective and accurate assessment of asymmetry and provide feedback to students and practitioners performing positional asymmetry tests of the pelvis.